PIT emulsions

ABSTRACT

PIT emulsions containing pesticides are comprised of: (a) from about 1% to about 20% by weight of a pesticide; (b) from about 5% to about 15% by weight of a nonionic emulsifier; (c) from about 0 to about 40% of a nonpolar solvent. These emulsions exhibit improved storage stability and higher activity compared with conventional pesticide emulsions.

This application is a 371 of PCT/EP00/01311 filed Feb. 18, 2000.

BACKGROUND OF THE INVENTION

This invention relates generally to pesticide formulations and moreparticularly to special PIT emulsions containing pesticides and selectedemulsifiers.

PRIOR ART

Emulsions of oil-soluble pesticides are frequently used in agricultureto protect valuable crops against pest infestation. Unfortunately, thesepreparations are not sufficiently stable in storage and, in particular,do not allow either the preparation of dilute forms or the addition ofwater-soluble pesticides without the emulsion breaking. Another problemis that the activity of the emulsions is not always satisfactory.

Accordingly, the complex addressed by the present invention was toprovide new plant protection compositions containing both solid andliquid, preferably oil-soluble pesticides which would be distinguishedby higher storage stability and activity and which, in particular, couldbe readily diluted with water and would allow the stable incorporationof additional water-soluble pesticides.

DESCRIPTION OF THE INVENTION

The present invention relates to PIT emulsions containing

(a) pesticides and

(b) nonionic emulsifiers.

It has now surprisingly been found that emulsions which contain thepesticides together with nonionic emulsifiers, more particularlycombinations of fatty alcohol ethoxylates and fatty acid partialglycerides and which have been prepared by the phase inversiontemperature method (PIT emulsions) excellently satisfy the complexrequirement profile. The preparations are distinguished by improvedstorage stability and higher activity compared with conventionalemulsions. In addition, they may readily be diluted with water and, inaddition, allow the subsequent incorporation of water-solublepesticides.

Pesticides

The pesticides which form component (a) are preferably oil-solublesubstances. Fungicides, herbicides, insecticides or mixtures thereof maybe used. Typical examples of suitable fungicides are azoxystrobin,benalaxyl, carbendazim, chlorothalonil, cupfer, cymoxanil, cyproconazol,diphenoconazol, dinocap, epoxiconazol, fluazinam, flusilazol,flutriafol, folpel, fosetyl aluminium, kresoxim methyl, hexaconazol,mancozeb, metalaxyl, metaconazol, myclobutanil, ofurace,phentinhydroxide, prochloraz, pyremethanil, soufre, tebuconazol andtetraconazol and mixtures thereof. The herbicides may be selected fromalachlor, acloniphen, acetochlor, amidosulfuron, aminotriazol, atrazin,bentazon, biphenox, bromoxyl octanoate, bromoxynil, clethodim,chlodinafop propargyl, chloridazon, chlorsulfuron, chlortoluron,clomazon, cycloxydim, desmedipham, dicamba, dicyclofop methyl, diurea,difluphenicanil, dimithenamid, ethofumesat, fluazifop,fluazifop-p-butyl, fluorochloridon, fluroxypyr, glufonsinat, glyphosat,haloxyfop-R, ioxynil octanoate, isoproturon, isoxaben, metamitron,metazachlor, metolachlor, metsulfuron methyl, nicosulfuron, notflurazon,oryzalin, oxadiazon, oxyfluorphen, paraquat, pendimethalin,phenmedipham, phenoxyprop-p-ethyl, propaquizafop, prosulfocarb,quizalofop, sulcotrion, sulphosat, terbutylazin, triasulfuron,trichlorpyr, triflualin and triflusulfuron methyl either individually orin combination with one another. Finally, suitable insecticides arebiphenthrin, carbofuran, carbosulfan, chlorpyriphos methyl,chlorpyriphos ethyl, β-cyfluthrin, λ-cyhalothrin, cyhexatin,cypermethrin, dicofol, endosulfan, τ-fluvalinat, α-methrin, δ-methrin,phenbutatin, pyrimicarb, terbuphos and tebuphenpyrad and mixturesthereof. Other suitable pesticides can be found, for example, in theIndex Phytosanitaire 1998, 34th Edition (published by Association deCoordination Technique Agricole, Paris).

Nonionic Emulsifiers

Suitable emulsifiers which form component (b) are, for example, nonionicsurfactants from at least one of the following groups:

(1) products of the addition of 2 to 30 moles of ethylene oxide and/or 0to 5 moles of propylene oxide onto linear fatty alcohols containing 8 to22 carbon atoms, onto fatty acids containing 12 to 22 carbon atoms andonto alkylphenols containing 8 to 15 carbon atoms in the alkyl group;

(2) C_(12/18) fatty acid monoesters and diesters of products of theaddition of 1 to 30 moles of ethylene oxide onto glycerol;

(3) glycerol monoesters and diesters and sorbitan monoesters anddiesters of saturated and unsaturated fatty acids containing 6 to 22carbon atoms and ethylene oxide adducts thereof;

(4) alkyl mono- and oligoglycosides containing 8 to 22 carbon atoms inthe alkyl group and ethoxylated analogs thereof;

(5) products of the addition of 15 to 60 moles of ethylene oxide ontocastor oil and/or hydrogenated castor oil;

(6) polyol esters and, in particular, polyglycerol esters such as, forexample, polyglycerol polyricinoleate or polyglycerolpoly-12-hydroxystearate. Mixtures of compounds from several of theseclasses are also suitable;

(7) products of the addition of 2 to 15 moles of ethylene oxide ontocastor oil and/or hydrogenated castor oil;

(8) partial esters based on linear, branched, unsaturated or saturatedC_(6/22) fatty acids, ricinoleic acid and 12-hydroxystearic acid andglycerol, polyglycerol, pentaerythritol, dipentaerythritol, sugaralcohols (for example sorbitol), alkyl glucosides (for example methylglucoside, butyl glucoside, lauryl glucoside) and polyglucosides (forexample cellulose);

(9) trialkyl phosphates and mono-, di- and/or tri-PEG-alkyl phosphates;

(10) wool wax alcohols;

(11) polysiloxane/polyalkyl polyether copolymers and correspondingderivatives;

(12) mixed esters of pentaerythritol, fatty acids, citric acid and fattyalcohol according to DE-PS 1165574 and/or mixed esters of fatty acidscontaining 6 to 22 carbon atoms, methyl glucose and polyols, preferablyglycerol,

(13) polyalkylene glycols and

(14) glycerol carbonate.

The addition products of ethylene oxide and/or propylene oxide withfatty alcohols, fatty acids, alkylphenols, glycerol mono- and diestersand sorbitan mono- and diesters of fatty acids or with castor oil areknown commercially available products. They are homolog mixtures ofwhich the average degree of alkoxylation corresponds to the ratiobetween the quantities of ethylene oxide and/or propylene oxide andsubstrate with which the addition reaction is carried out. C_(2/18)fatty acid monoesters and diesters of adducts of ethylene oxide withglycerol are known as refatting agents for cosmetic formulations fromDE-PS 2024051.

C_(8/18) alkyl mono- and oligoglycosides, their production and their useas surfactants are known, for example, from U.S. Pat. No. 3,839,318,U.S. Pat. No. 3,707,535, U.S. Pat. No. 3,547,828, DE-OS 1943689, DE-OS2036472 and DE-A1 3001064 and from EP-A1 0 077 167. They are produced inparticular by reaction of glucose or oligosaccharides with primaryalcohols containing 8 to 18 C atoms. So far as the glycoside componentis concerned, both monoglycosides, in which a cyclic sugar unit isattached to the fatty alcohol by a glycoside linkage, and oligomericglycosides with a degree of oligomerization of preferably up to about 8are suitable. The degree of oligomerization is a statistical mean valueon which a homolog distribution typical of such technical products isbased.

A preferred embodiment of the invention is characterized by the use ofmixtures of at least two nonionic emulsifiers, more particularly (b1)fatty alcohol ethoxylates and (b2) fatty acid partial glycerides. Thefatty alcohol ethoxylates (component b1) preferably correspond toformula (I):

R¹O(CH₂CH₂O)_(n)H  (I)

in which R¹ is a linear or branched alkyl and/or alkenyl groupcontaining 12 to 24 and more particularly 16 to 22 carbon atoms and n isa number of 1 to 30 and more particularly 10 to 20. Typical examples areproducts of the addition of on average 10 to 20 moles of ethylene oxideonto cetyl alcohol, stearyl alcohol, isostearyl alcohol, cetearylalcohol and behenyl alcohol. The fatty acid partial glycerides, i.e.monoglycerides, diglycerides and technical mixtures thereof, which maystill contain small quantities of triglycerides from their productionand which form component (b2), generally correspond to formula (II):

in which R²CO is a linear or branched, saturated and/or unsaturated acylgroup containing 6 to 22 and preferably 12 to 18 carbon atoms, R³ and R⁴independently of one another have the same meaning as R²CO or representOH and the sum (m+p+q) is 0 or a number of 1 to 100 and preferably 5 to25, with the proviso that at least one of the two substituents R³ and R⁴represents OH. Typical examples are mono- and/or diglycerides based oncaproic acid, caprylic acid, 2-ethylhexanoic acid, capric acid, lauricacid, isotridecanoic acid, myristic acid, palmitic acid, palmitoleicacid, stearic acid, isostearic acid, oleic acid, elaidic acid,petroselic acid, linoleic acid, linolenic acid, elaeostearic acid,arachic acid, gadoleic acid, behenic acid and erucic acid and technicalmixtures thereof. Technical lauric acid glycerides, palmitic acidglycerides, stearic acid glycerides, isostearic acid glycerides, oleicacid glycerides, behenic acid glycerides and/or erucic acid glycerideswhich have a monoglyceride content of 50 to 95% by weight and preferably60 to 90% by weight are preferably used. The ratio in which the fattyalcohol ethoxylates and fatty acid partial glycerides are used isnon-critical within wide limits and may be 90:10 to 10:90, preferably75:25 to 25:75 and more particularly 60:40 to 40:60 parts by weight.

Solvents

Particularly when pesticides solid at room temperature are to beincorporated in the emulsions, it is advisable to use nonpolar solvents.This optional component (c) may be selected, for example, from mineraloils, fatty acid lower alkyl esters such as, for example, the C₁₋₄esters, i.e. methyl, ethyl, propyl and/or butyl esters, of caproic acid,caprylic acid, 2-ethylhexanoic acid, capric acid, lauric acid,isotridecanoic acid, myristic acid, palmitic acid, palmitoleic acid,stearic acid, isostearic acid, oleic acid, elaidic acid, petroselicacid, linoleic acid, linolenic acid, elaeostearic acid, arachic acid,gadoleic acid, behenic acid and erucic acid and technical mixturesthereof. Vegetable triglycerides, for example coconut oil, palm oil,palm kernel oil, sunflower oil, olive oil and the like, are alsosuitable.

PIT Emulsions

In one preferred embodiment, the PIT emulsions according to theinvention contain

(a) 1 to 20, preferably 5 to 15% by weight of pesticides,

(b) 5 to 15, preferably 8 to 12% by weight of nonionic emulsifiers and

(c) 0 to 40, preferably 5 to 30% by weight of solvents,

with the proviso that the quantities shown add up to 100% by weight withwater and optionally other typical auxiliaries and additives. The watercontent of the emulsions is on average 30 to 90 and more particularly 40to 60% by weight while the droplet size is between 0.01 and 1 μm andpreferably between 0.1 and 0.5 μm.

The present invention also relates to a process for the production ofpesticide emulsions in which the oil-soluble pesticides are homogenizedtogether with the nonionic emulsifiers and 40 to 60% by weight, based onthe final formulation, of water and heated beyond the phase inversiontemperature, the remaining water is added, the emulsion is left to cooland is then optionally diluted with more water to the requiredactive-substance concentration and/or other water-soluble pesticides areadded.

EXAMPLES

Plant protection emulsions using pesticides liquid or solid at roomtemperature were used. Emulsions 1 to 3 according to the invention wereprepared by the PIT method while comparison emulsions C1 and C2 wereprepared by the conventional hot method. The emulsions were then storedfor 1 week at 20° C. and for 4 weeks at 40° C. and stability-tested;(++) means stable, (+) means slight clouding and (−) means phaseseparation. In addition, the prepared emulsions were diluted with waterat 20° C. to an active substance content of 1% by weight and evaluatedfor stability in the same way. The results are set out in Table 1.

TABLE 1 Stability of pesticide formulations Composition/performance 1 23 C1 C2 Pesticide (Mp. < 20° C.) 5.0 5.0 —  5.0 5.0 Pesticide (Mp. > 25°C.) — — 5.0 — — Cetyl stearyl alcohol + 12 EO 12.0 8.0 — 12.0 8.0Behenyl alcohol + 10 EO — — 8.0 — — Glyceryl Stearate — 4.0 4.0 — 4.0Coconut fatty acid — — 20.0 — — methyl ester Water to 100 Averageparticle size [μm] <1 <1 <1 10-100 10-100 Stability after storage (1week, 20° C.) ++ ++ ++ + + after storage (4 weeks, + ++ ++ − − 40° C.)after dilution with water + + + − −

The PIT emulsions according to the invention were found to be stableboth under temperature stress and in diluted form whereas the comparisonemulsions allowed neither temperature stress nor the addition of water.

What is claimed is:
 1. A composition comprising: (a) from about 1 to 20%by weight of an oil-soluble pesticide; (b) from about 5 to 15% by weightof a nonionic emulsifier containing a fatty alcohol ethoxylate and afatty acid partial glyceride; (c) up to about 40% by weight of anon-polar solvent; and (d) remainder, to 100%, water, and wherein thecomposition is a PIT (Phase inversion temperature) emulsion.
 2. Thecomposition of claim 1 wherein the oil-soluble pesticide is selectedfrom the group consisting of a fungicide, an herbicide, an insecticide,and mixtures thereof.
 3. The composition of claim 1 wherein theoil-soluble pesticide is present in the composition in an amount of fromabout 5 to 15% by weight, based on the weight of the composition.
 4. Thecomposition of claim 1 wherein the nonionic emulsifier is present in thecomposition in an amount of from about 8 to 12% by weight, based on theweight of the composition.
 5. The composition of claim 1 wherein thenon-polar solvent is a C₁₋₄ alkyl ester.
 6. The composition of claim 1wherein the non-polar solvent is present in the composition in an amountof from about 5 to 30% by weight, based on the weight of thecomposition.
 7. A process for treating crop comprising contacting saidcrop with a pesticide composition comprising: (a) from about 1 to 20% byweight of an oil-soluble pesticide; (b) from about 5 to 15% by weight ofa nonionic emulsifier containing a fatty alcohol ethoxylate and fattyacid partial glyceride; (c) remainder, to 100% by weight, water andwherein the composition is a PIT emulsion.
 8. The process of claim 7wherein the oil-soluble pesticide is selected from the group consistingof a fungicide, an herbicide, an insecticide, and mixtures thereof. 9.The process of claim 7 wherein the oil-soluble pesticide is present inthe composition in an amount of from about 5 to 15% by weight, based onthe weight of the composition.
 10. The process of claim 7 wherein thenonionic emulsifier is present in the composition in an amount of fromabout 8 to 12% by weight, based on the weight of the composition. 11.The process of claim 7 wherein the composition further comprises anon-polar solvent that is a C₁₋₄ alkyl ester.
 12. The process of claim 7wherein the composition further comprises a non-polar solvent that ispresent in the composition in an amount of from about 5 to 30% byweight, based on the weight of the composition.